/*-+-*****************************************************************************
 Copyright (C) 2009-2012 Oceanside Software Corporation (R)
 Dallas, Texas

 Author       : Jason T. Brower
 Purpose      : This file is part of a point-of-sale software package
                originally written for Table-Service Restaurants.
              
 Date         : July 8th of 2012
              
 History      : The application that this software file belongs to was 
                written over a 3-Year period.  The first version was written
                in C# .Net 3.5 using Windows Forms.  Being new to .Net at
                the time, I soon learned of Windows Presentation Foundation,
                liked the graphics capabilities and databinding so I
                migrated to WPF.  When the .Net 4.0 framework was released
                the application was migrated from 3.5 to 4.0. Now today,
                .Net 4.5 RC is out and I was already in process of migrating
                before I made this public.
                
Excuse Me     : Please excuse the coding style, it is not representative of
                my typical work.  During the three years I was under a very
                tight budget, constantly running out of funding and was 
                working 18 hour days hyped up on 5-Hour Energy.  The 
                design is not textbook.  It is monolythic because of
                previous issues I will not get into.  There are few comments
                in the code and the ones that are there may be incorrect.
                
What it is not: This is not the exact version that I took through PA-DSS 2.0
                nor is it the exact version running at my customer sites.
                I removed some details for security purposes including some
                encryption algorithms.  The reporting was removed because
                I was including a third party library that cannot be 
                published with this Open Source.
                
What it is    : This application has been running at high volume restaraunts
                for over a year.  It never freezes, crashes or does anything
                unexpected.  So long as it is built, installed and configured
                correctly, it is a strong system that we can all enhance.

Contact       : Please note that I can no longer work for free.  However, you
                can reach me at information@oceansidesw.com.                                                      

*********************************************************************************/
using System;
using System.Collections.ObjectModel;
using System.Threading;
using System.Windows.Threading;

namespace Oceanside
{
    [Serializable]
    public class ThreadSafeObservableCollection<T> : ObservableCollection<T>
    {
        [NonSerialized]
        ReaderWriterLock _lock = null;

        public ThreadSafeObservableCollection()
        {
        }

        protected override void ClearItems()
        {
            try
            {
                if (Constants.MainDispatcher.CheckAccess())
                {
                    if (null == _lock)
                    {
                        _lock = new ReaderWriterLock();
                    }
                    LockCookie c = _lock.UpgradeToWriterLock(-1);
                    base.ClearItems();
                    _lock.DowngradeFromWriterLock(ref c);
                }
                else
                {
                    Constants.MainDispatcher.Invoke(DispatcherPriority.DataBind, (SendOrPostCallback)delegate { Clear(); });
                }
            }
            catch (Exception ex)
            {
                Logging.LogException(ex);
            }
        }
        protected override void InsertItem(int index, T item)
        {
            try
            {
                if (Constants.MainDispatcher.CheckAccess())
                {
                    if (index > this.Count)
                        return;
                    if (null == _lock)
                    {
                        _lock = new ReaderWriterLock();
                    }
                    LockCookie c = _lock.UpgradeToWriterLock(-1);
                    base.InsertItem(index, item);
                    _lock.DowngradeFromWriterLock(ref c);
                }
                else
                {
                    object[] e = new object[] { index, item };
                    Constants.MainDispatcher.Invoke(DispatcherPriority.DataBind, (SendOrPostCallback)delegate { InsertItemImpl(e); }, e);
                }
            }
            catch (Exception ex)
            {
                Logging.LogException(ex);
            }
        }
        void InsertItemImpl(object[] e)
        {
            try
            {
                if (Constants.MainDispatcher.CheckAccess())
                {
                    InsertItem((int)e[0], (T)e[1]);
                }
                else
                {
                    Constants.MainDispatcher.Invoke(DispatcherPriority.DataBind, (SendOrPostCallback)delegate { InsertItemImpl(e); });
                }
            }
            catch (Exception ex)
            {
                Logging.LogException(ex);
            }
        }
        protected override void MoveItem(int oldIndex, int newIndex)
        {
            try
            {
                if (Constants.MainDispatcher.CheckAccess())
                {
                    if (oldIndex >= this.Count | newIndex >= this.Count | oldIndex == newIndex)
                        return;
                    if (null == _lock)
                    {
                        _lock = new ReaderWriterLock();
                    }
                    LockCookie c = _lock.UpgradeToWriterLock(-1);
                    base.MoveItem(oldIndex, newIndex);
                    _lock.DowngradeFromWriterLock(ref c);
                }
                else
                {
                    object[] e = new object[] { oldIndex, newIndex };
                    Constants.MainDispatcher.Invoke(DispatcherPriority.DataBind, (SendOrPostCallback)delegate { MoveItemImpl(e); }, e);
                }
            }
            catch (Exception ex)
            {
                Logging.LogException(ex);
            }
        }
        void MoveItemImpl(object[] e)
        {
            try
            {
                if (Constants.MainDispatcher.CheckAccess())
                {
                    MoveItem((int)e[0], (int)e[1]);
                }
                else
                {
                    Constants.MainDispatcher.Invoke(DispatcherPriority.DataBind, (SendOrPostCallback)delegate { MoveItemImpl(e); });
                }
            }
            catch (Exception ex)
            {
                Logging.LogException(ex);
            }
        }
        protected override void RemoveItem(int index)
        {
            try
            {
                if (Constants.MainDispatcher.CheckAccess())
                {
                    if (index >= this.Count)
                        return;
                    if (null == _lock)
                    {
                        _lock = new ReaderWriterLock();
                    }
                    LockCookie c = _lock.UpgradeToWriterLock(-1);
                    base.RemoveItem(index);
                    _lock.DowngradeFromWriterLock(ref c);
                }
                else
                {
                    Constants.MainDispatcher.Invoke(DispatcherPriority.DataBind, (SendOrPostCallback)delegate { RemoveItem(index); }, index);
                }
            }
            catch (Exception ex)
            {
                Logging.LogException(ex);
            }
        }
        protected override void SetItem(int index, T item)
        {
            try
            {
                if (Constants.MainDispatcher.CheckAccess())
                {
                    if (null == _lock)
                    {
                        _lock = new ReaderWriterLock();
                    }
                    LockCookie c = _lock.UpgradeToWriterLock(-1);
                    base.SetItem(index, item);
                    _lock.DowngradeFromWriterLock(ref c);
                }
                else
                {
                    object[] e = new object[] { index, item };
                    Constants.MainDispatcher.Invoke(DispatcherPriority.DataBind, (SendOrPostCallback)delegate { SetItemImpl(e); }, e);
                }
            }
            catch (Exception ex)
            {
                Logging.LogException(ex);
            }
        }
        void SetItemImpl(object[] e)
        {
            try
            {
                if (Constants.MainDispatcher.CheckAccess())
                {
                    SetItem((int)e[0], (T)e[1]);
                }
                else
                {
                    Constants.MainDispatcher.Invoke(DispatcherPriority.DataBind, (SendOrPostCallback)delegate { SetItemImpl(e); });
                }
            }
            catch (Exception ex)
            {
                Logging.LogException(ex);
            }
        }
    }
}
